“With the winter approaching it is necessary that we prepare ourselves for the possible challenges we know we will be experiencing in respect of electricity provision. The municipality is envisaging a bleak winter in this respect. Currently key points within the municipal electrical infrastructure are under severe strain due to a peak in demand largely as a result of the winter months that are approaching and increased demand,” Mr Theo van Vuuren, the city’s administrator painted the gloomy picture.
No one has to highlight it as everybody knows that the main contributing factors of power supply interruptions are the age old infrastructure, couple that with overloading and also illegal usage of electricity and you have disaster spelled in capital letters.
The main focus points which are severely affected at this stage are consumers supplied from Doornpoort Substation on the Eastern Suburbs, KwaGuqa 132kV Substations on the Western areas and Phola Substation which is situated within Phola Township. Various other intakes will also be affected but not to a large scale as the abovementioned intake points.
The notified maximum demand from Eskom at this supply point at Doornpoort Substation is 48MVA and the municipality is currently utilizing 60MVA.
This substation is severely being overloaded as 70 % of households in the Eastern Suburbs including the high business areas such as Highveld Mall, the Ridge Casino and critical water supply system are all being fed from this supply point.
From Doornpoort Substation electricity is distributed to Paul Sauer-, Kiepersol-, Dixon-, Malherbe-, Del Judor-, Dam-, Doornpoort-, Modelpark-, Blanchville- and Driehoek Substation.
These substations are currently in a dilapidated state and the equipment is outdated and not functioning optimally, which results in continuous interruptions and wherein protection equipment does not arrest faults timeously causing the equipment to trip intermittently.
Some of the substations such as Dixon, Kiepersol, Malherbe and Del Judor have been vandalized and are currently operated in an unsafe state.
“We have secured these substations and tried to prevent them to be vandalized. To upgrade these substations will cost us approximately R100 million, money which at this stage we do not have,” Van Vuuren said and he added, “The capacity of these stations is most likely to be exceeded on a regular basis and that will cause any one or more than one of the stations to trip. To correct this means we need to wait for demand to decrease and to switch on in stages. These problems normally are quickly repaired.”
A further factor is the fact that the main feeder and connector cables are old, some already past their economical life time, and most are under ground.
“Power interruptions and surges have a high impact on these lines and if the past years are any indication, we can expect multiple cable burns on these lines. Fault finding and pinpointing of underground cable faults takes much longer due to the fact that our protection equipment is not functioning correctly making locating and isolating difficult.”
Distances between substations also plays a major role as some of the bulk cables are in excess of 5km between substations. Access to some private properties to which municipal services run are not easily accessible due to land owners not being available.
“The above are factors which will imply that we will experience outages and when that happens it may take six hours to 24 hours at a time to restore power. “
Due to the existence of ring-feed supplies, some areas can be supplied from different substations depending on the existing network capacity.
The notified maximum demand from Eskom to KwaGuqa 132KV Substation is 40MVA and yet the municipality has no alternative as to maximising its demand by utilizing 55MVA.
In October last year an incident occurred at the substation wherein the main 40MVA transformer caught fire which spread to the building housing switching equipment and resulted in damages estimated to be at R30m. A temporary installation was done at the substation in order to supply electricity to consumers whilst waiting for finalization of the insurance claim for restoring the substation to its normal operational status.
The situation at the substation is currently of such a nature that it is being operated on a one 30MVA transformer and temporary outdoor switchgear instead of the normal two 40MVA transformers. This has resulted in limitations with regards to the expected loads and has placed severe strain on the ability to supply the required demand to the community. The substation will not be completed and returned to its normality before the end of the year as negotiations with the insurers are still pending.
“If we do not get the substation fully restored before peak demand kicks in, we will experience regular power outages as a result of over loading this winter,” said Van Vuuren.
KwaGuqa Substation is the main feeder supply to 132kV KwaGuqa Substation, ring Substation 3, Ring Substation 1, Ring Substation 4, Ring Substation 5, and Mpumelelweni Substation.
Protection systems at this substation are non-functional due to the fact that it is currently being operated on a temporary state. The prevalence of illegal connections poses a serious risk to the stability of the network as well as damage to equipment such as transformers and cables.
On the positive side most of the feeder cables are in a better shape than in the eastern areas and less cable burns are likely.
However, transformers in areas close to informal settlements are often targeted by illegal connections and are more prone to overloading on a block basis and especially burnouts. When that happens these transformers need to be replaced and this often takes time depending on stock levels. The most likely areas to be affected by block outages due to transformer and cable failures to illegal connections and overloading is KwaGuqa extensions 10, 11, 15, 16, 17 (Vosman) and Hlalanikahle extensions.
Also Phola Substation is been strangled to manoeuvre every ounce of electricity out of it. This substation is a 6MVA, but the municipality has doubled its demand and is squeezing 12MVA out of it.
The substation is currently operated utilizing a temporary arrangement as an incident occurred during 2010 wherein a fire destroyed the distribution equipment at the substation. The capacity on this substation is over stretched to an extent where the municipality has no option but to apply load shedding during the winter months, as there is no alternative arrangement currently available to cope with the loads.
“The above implies that this substation is not stable and is overloaded. This will be worse during peak times and we can expect regular outages. We are in a process with the mining companies to look at the upgrading of the substation and progress during the period will be possible but, to increase the capacity input from Eskom to above the current supply will possibly take years,” Van Vuuren said.
Van Vuuren said the municipality’s electrical department is still busy with work within available means to try and stabilize the system as far as possible to minimize problems.
“In addition we are also busy with testing protective structures to protect the network against unauthorized use and we will be changing to time of use tariffs to try and equalize power demand. The teams have been strengthened and we are also getting additional vehicles in place to empower them to attend to any crisis in as short as possible time. We also have appointed a panel of contractors from which additional assistance will be mobilized as required.”
The municipality is also currently embarking on fencing off all critical substations in an effort to make them safer.
It should also be noted that the municipality with the assistance from the community can reduce load through the ripple control system, by switching off geysers to households in the event of the loads becoming too high. It should be noted that numerous power outages are caused by unauthorized trenching within the Emalahleni jurisdiction.
Eskom called on all consumers to pull together to help beat the peak over the next few months by using electricity sparingly particularly from 17:00 and 21:00.
“We request all electricity customers to save at least 10% of their electricity usage and sustain these savings. Residential and commercial customers can make the biggest difference by switching off geysers and pool pumps during peak hours, switching off non-essential lights and using space-heating efficiently,” a statement by Eskom read.
Eskom’s power system is expected to remain tight over the evening peaks for the rest of the week due to higher demand with the colder weather conditions.
All indications are that load shedding by Eskom will be a reality this winter. Should this happen the arrangement is that the municipality will be notified. There will be all attempts made that disruptions are controlled and staged with power cuts to different areas at predetermined times.
